1 // SPDX-License-Identifier: GPL-2.0-only 2 #define pr_fmt(fmt) "IPsec: " fmt 3 4 #include <crypto/aead.h> 5 #include <crypto/authenc.h> 6 #include <linux/err.h> 7 #include <linux/module.h> 8 #include <net/ip.h> 9 #include <net/xfrm.h> 10 #include <net/esp.h> 11 #include <linux/scatterlist.h> 12 #include <linux/kernel.h> 13 #include <linux/pfkeyv2.h> 14 #include <linux/rtnetlink.h> 15 #include <linux/slab.h> 16 #include <linux/spinlock.h> 17 #include <linux/in6.h> 18 #include <net/icmp.h> 19 #include <net/protocol.h> 20 #include <net/udp.h> 21 #include <net/tcp.h> 22 #include <net/espintcp.h> 23 #include <linux/skbuff_ref.h> 24 25 #include <linux/highmem.h> 26 27 struct esp_skb_cb { 28 struct xfrm_skb_cb xfrm; 29 void *tmp; 30 }; 31 32 struct esp_output_extra { 33 __be32 seqhi; 34 u32 esphoff; 35 }; 36 37 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 38 39 /* 40 * Allocate an AEAD request structure with extra space for SG and IV. 41 * 42 * For alignment considerations the IV is placed at the front, followed 43 * by the request and finally the SG list. 44 * 45 * TODO: Use spare space in skb for this where possible. 46 */ 47 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen) 48 { 49 unsigned int len; 50 51 len = extralen; 52 53 len += crypto_aead_ivsize(aead); 54 55 if (len) { 56 len += crypto_aead_alignmask(aead) & 57 ~(crypto_tfm_ctx_alignment() - 1); 58 len = ALIGN(len, crypto_tfm_ctx_alignment()); 59 } 60 61 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 62 len = ALIGN(len, __alignof__(struct scatterlist)); 63 64 len += sizeof(struct scatterlist) * nfrags; 65 66 return kmalloc(len, GFP_ATOMIC); 67 } 68 69 static inline void *esp_tmp_extra(void *tmp) 70 { 71 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 72 } 73 74 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen) 75 { 76 return crypto_aead_ivsize(aead) ? 77 PTR_ALIGN((u8 *)tmp + extralen, 78 crypto_aead_alignmask(aead) + 1) : tmp + extralen; 79 } 80 81 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 82 { 83 struct aead_request *req; 84 85 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 86 crypto_tfm_ctx_alignment()); 87 aead_request_set_tfm(req, aead); 88 return req; 89 } 90 91 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 92 struct aead_request *req) 93 { 94 return (void *)ALIGN((unsigned long)(req + 1) + 95 crypto_aead_reqsize(aead), 96 __alignof__(struct scatterlist)); 97 } 98 99 static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb) 100 { 101 struct crypto_aead *aead = x->data; 102 int extralen = 0; 103 u8 *iv; 104 struct aead_request *req; 105 struct scatterlist *sg; 106 107 if (x->props.flags & XFRM_STATE_ESN) 108 extralen += sizeof(struct esp_output_extra); 109 110 iv = esp_tmp_iv(aead, tmp, extralen); 111 req = esp_tmp_req(aead, iv); 112 113 /* Unref skb_frag_pages in the src scatterlist if necessary. 114 * Skip the first sg which comes from skb->data. 115 */ 116 if (req->src != req->dst) 117 for (sg = sg_next(req->src); sg; sg = sg_next(sg)) 118 skb_page_unref(sg_page(sg), skb->pp_recycle); 119 } 120 121 #ifdef CONFIG_INET_ESPINTCP 122 struct esp_tcp_sk { 123 struct sock *sk; 124 struct rcu_head rcu; 125 }; 126 127 static void esp_free_tcp_sk(struct rcu_head *head) 128 { 129 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu); 130 131 sock_put(esk->sk); 132 kfree(esk); 133 } 134 135 static struct sock *esp_find_tcp_sk(struct xfrm_state *x) 136 { 137 struct xfrm_encap_tmpl *encap = x->encap; 138 struct net *net = xs_net(x); 139 struct esp_tcp_sk *esk; 140 __be16 sport, dport; 141 struct sock *nsk; 142 struct sock *sk; 143 144 sk = rcu_dereference(x->encap_sk); 145 if (sk && sk->sk_state == TCP_ESTABLISHED) 146 return sk; 147 148 spin_lock_bh(&x->lock); 149 sport = encap->encap_sport; 150 dport = encap->encap_dport; 151 nsk = rcu_dereference_protected(x->encap_sk, 152 lockdep_is_held(&x->lock)); 153 if (sk && sk == nsk) { 154 esk = kmalloc(sizeof(*esk), GFP_ATOMIC); 155 if (!esk) { 156 spin_unlock_bh(&x->lock); 157 return ERR_PTR(-ENOMEM); 158 } 159 RCU_INIT_POINTER(x->encap_sk, NULL); 160 esk->sk = sk; 161 call_rcu(&esk->rcu, esp_free_tcp_sk); 162 } 163 spin_unlock_bh(&x->lock); 164 165 sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4, 166 dport, x->props.saddr.a4, sport, 0); 167 if (!sk) 168 return ERR_PTR(-ENOENT); 169 170 if (!tcp_is_ulp_esp(sk)) { 171 sock_put(sk); 172 return ERR_PTR(-EINVAL); 173 } 174 175 spin_lock_bh(&x->lock); 176 nsk = rcu_dereference_protected(x->encap_sk, 177 lockdep_is_held(&x->lock)); 178 if (encap->encap_sport != sport || 179 encap->encap_dport != dport) { 180 sock_put(sk); 181 sk = nsk ?: ERR_PTR(-EREMCHG); 182 } else if (sk == nsk) { 183 sock_put(sk); 184 } else { 185 rcu_assign_pointer(x->encap_sk, sk); 186 } 187 spin_unlock_bh(&x->lock); 188 189 return sk; 190 } 191 192 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 193 { 194 struct sock *sk; 195 int err; 196 197 rcu_read_lock(); 198 199 sk = esp_find_tcp_sk(x); 200 err = PTR_ERR_OR_ZERO(sk); 201 if (err) 202 goto out; 203 204 bh_lock_sock(sk); 205 if (sock_owned_by_user(sk)) 206 err = espintcp_queue_out(sk, skb); 207 else 208 err = espintcp_push_skb(sk, skb); 209 bh_unlock_sock(sk); 210 211 out: 212 rcu_read_unlock(); 213 return err; 214 } 215 216 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 217 struct sk_buff *skb) 218 { 219 struct dst_entry *dst = skb_dst(skb); 220 struct xfrm_state *x = dst->xfrm; 221 222 return esp_output_tcp_finish(x, skb); 223 } 224 225 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 226 { 227 int err; 228 229 local_bh_disable(); 230 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 231 local_bh_enable(); 232 233 /* EINPROGRESS just happens to do the right thing. It 234 * actually means that the skb has been consumed and 235 * isn't coming back. 236 */ 237 return err ?: -EINPROGRESS; 238 } 239 #else 240 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 241 { 242 WARN_ON(1); 243 return -EOPNOTSUPP; 244 } 245 #endif 246 247 static void esp_output_done(void *data, int err) 248 { 249 struct sk_buff *skb = data; 250 struct xfrm_offload *xo = xfrm_offload(skb); 251 void *tmp; 252 struct xfrm_state *x; 253 254 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 255 struct sec_path *sp = skb_sec_path(skb); 256 257 x = sp->xvec[sp->len - 1]; 258 } else { 259 x = skb_dst(skb)->xfrm; 260 } 261 262 tmp = ESP_SKB_CB(skb)->tmp; 263 esp_ssg_unref(x, tmp, skb); 264 kfree(tmp); 265 266 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 267 if (err) { 268 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 269 kfree_skb(skb); 270 return; 271 } 272 273 skb_push(skb, skb->data - skb_mac_header(skb)); 274 secpath_reset(skb); 275 xfrm_dev_resume(skb); 276 } else { 277 if (!err && 278 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 279 esp_output_tail_tcp(x, skb); 280 else 281 xfrm_output_resume(skb->sk, skb, err); 282 } 283 } 284 285 /* Move ESP header back into place. */ 286 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 287 { 288 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 289 void *tmp = ESP_SKB_CB(skb)->tmp; 290 __be32 *seqhi = esp_tmp_extra(tmp); 291 292 esph->seq_no = esph->spi; 293 esph->spi = *seqhi; 294 } 295 296 static void esp_output_restore_header(struct sk_buff *skb) 297 { 298 void *tmp = ESP_SKB_CB(skb)->tmp; 299 struct esp_output_extra *extra = esp_tmp_extra(tmp); 300 301 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 302 sizeof(__be32)); 303 } 304 305 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb, 306 struct xfrm_state *x, 307 struct ip_esp_hdr *esph, 308 struct esp_output_extra *extra) 309 { 310 /* For ESN we move the header forward by 4 bytes to 311 * accommodate the high bits. We will move it back after 312 * encryption. 313 */ 314 if ((x->props.flags & XFRM_STATE_ESN)) { 315 __u32 seqhi; 316 struct xfrm_offload *xo = xfrm_offload(skb); 317 318 if (xo) 319 seqhi = xo->seq.hi; 320 else 321 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 322 323 extra->esphoff = (unsigned char *)esph - 324 skb_transport_header(skb); 325 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 326 extra->seqhi = esph->spi; 327 esph->seq_no = htonl(seqhi); 328 } 329 330 esph->spi = x->id.spi; 331 332 return esph; 333 } 334 335 static void esp_output_done_esn(void *data, int err) 336 { 337 struct sk_buff *skb = data; 338 339 esp_output_restore_header(skb); 340 esp_output_done(data, err); 341 } 342 343 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb, 344 int encap_type, 345 struct esp_info *esp, 346 __be16 sport, 347 __be16 dport) 348 { 349 struct udphdr *uh; 350 unsigned int len; 351 struct xfrm_offload *xo = xfrm_offload(skb); 352 353 len = skb->len + esp->tailen - skb_transport_offset(skb); 354 if (len + sizeof(struct iphdr) > IP_MAX_MTU) 355 return ERR_PTR(-EMSGSIZE); 356 357 uh = (struct udphdr *)esp->esph; 358 uh->source = sport; 359 uh->dest = dport; 360 uh->len = htons(len); 361 uh->check = 0; 362 363 /* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload 364 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack. 365 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it. 366 */ 367 if (!xo || encap_type != UDP_ENCAP_ESPINUDP) 368 *skb_mac_header(skb) = IPPROTO_UDP; 369 370 return (struct ip_esp_hdr *)(uh + 1); 371 } 372 373 #ifdef CONFIG_INET_ESPINTCP 374 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 375 struct sk_buff *skb, 376 struct esp_info *esp) 377 { 378 __be16 *lenp = (void *)esp->esph; 379 struct ip_esp_hdr *esph; 380 unsigned int len; 381 struct sock *sk; 382 383 len = skb->len + esp->tailen - skb_transport_offset(skb); 384 if (len > IP_MAX_MTU) 385 return ERR_PTR(-EMSGSIZE); 386 387 rcu_read_lock(); 388 sk = esp_find_tcp_sk(x); 389 rcu_read_unlock(); 390 391 if (IS_ERR(sk)) 392 return ERR_CAST(sk); 393 394 *lenp = htons(len); 395 esph = (struct ip_esp_hdr *)(lenp + 1); 396 397 return esph; 398 } 399 #else 400 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 401 struct sk_buff *skb, 402 struct esp_info *esp) 403 { 404 return ERR_PTR(-EOPNOTSUPP); 405 } 406 #endif 407 408 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 409 struct esp_info *esp) 410 { 411 struct xfrm_encap_tmpl *encap = x->encap; 412 struct ip_esp_hdr *esph; 413 __be16 sport, dport; 414 int encap_type; 415 416 spin_lock_bh(&x->lock); 417 sport = encap->encap_sport; 418 dport = encap->encap_dport; 419 encap_type = encap->encap_type; 420 spin_unlock_bh(&x->lock); 421 422 switch (encap_type) { 423 default: 424 case UDP_ENCAP_ESPINUDP: 425 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport); 426 break; 427 case TCP_ENCAP_ESPINTCP: 428 esph = esp_output_tcp_encap(x, skb, esp); 429 break; 430 } 431 432 if (IS_ERR(esph)) 433 return PTR_ERR(esph); 434 435 esp->esph = esph; 436 437 return 0; 438 } 439 440 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 441 { 442 u8 *tail; 443 int nfrags; 444 int esph_offset; 445 struct page *page; 446 struct sk_buff *trailer; 447 int tailen = esp->tailen; 448 449 /* this is non-NULL only with TCP/UDP Encapsulation */ 450 if (x->encap) { 451 int err = esp_output_encap(x, skb, esp); 452 453 if (err < 0) 454 return err; 455 } 456 457 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 458 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 459 goto cow; 460 461 if (!skb_cloned(skb)) { 462 if (tailen <= skb_tailroom(skb)) { 463 nfrags = 1; 464 trailer = skb; 465 tail = skb_tail_pointer(trailer); 466 467 goto skip_cow; 468 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 469 && !skb_has_frag_list(skb)) { 470 int allocsize; 471 struct sock *sk = skb->sk; 472 struct page_frag *pfrag = &x->xfrag; 473 474 esp->inplace = false; 475 476 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 477 478 spin_lock_bh(&x->lock); 479 480 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 481 spin_unlock_bh(&x->lock); 482 goto cow; 483 } 484 485 page = pfrag->page; 486 get_page(page); 487 488 tail = page_address(page) + pfrag->offset; 489 490 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 491 492 nfrags = skb_shinfo(skb)->nr_frags; 493 494 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 495 tailen); 496 skb_shinfo(skb)->nr_frags = ++nfrags; 497 498 pfrag->offset = pfrag->offset + allocsize; 499 500 spin_unlock_bh(&x->lock); 501 502 nfrags++; 503 504 skb_len_add(skb, tailen); 505 if (sk && sk_fullsock(sk)) 506 refcount_add(tailen, &sk->sk_wmem_alloc); 507 508 goto out; 509 } 510 } 511 512 cow: 513 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 514 515 nfrags = skb_cow_data(skb, tailen, &trailer); 516 if (nfrags < 0) 517 goto out; 518 tail = skb_tail_pointer(trailer); 519 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 520 521 skip_cow: 522 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 523 pskb_put(skb, trailer, tailen); 524 525 out: 526 return nfrags; 527 } 528 EXPORT_SYMBOL_GPL(esp_output_head); 529 530 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 531 { 532 u8 *iv; 533 int alen; 534 void *tmp; 535 int ivlen; 536 int assoclen; 537 int extralen; 538 struct page *page; 539 struct ip_esp_hdr *esph; 540 struct crypto_aead *aead; 541 struct aead_request *req; 542 struct scatterlist *sg, *dsg; 543 struct esp_output_extra *extra; 544 int err = -ENOMEM; 545 546 assoclen = sizeof(struct ip_esp_hdr); 547 extralen = 0; 548 549 if (x->props.flags & XFRM_STATE_ESN) { 550 extralen += sizeof(*extra); 551 assoclen += sizeof(__be32); 552 } 553 554 aead = x->data; 555 alen = crypto_aead_authsize(aead); 556 ivlen = crypto_aead_ivsize(aead); 557 558 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 559 if (!tmp) 560 goto error; 561 562 extra = esp_tmp_extra(tmp); 563 iv = esp_tmp_iv(aead, tmp, extralen); 564 req = esp_tmp_req(aead, iv); 565 sg = esp_req_sg(aead, req); 566 567 if (esp->inplace) 568 dsg = sg; 569 else 570 dsg = &sg[esp->nfrags]; 571 572 esph = esp_output_set_extra(skb, x, esp->esph, extra); 573 esp->esph = esph; 574 575 sg_init_table(sg, esp->nfrags); 576 err = skb_to_sgvec(skb, sg, 577 (unsigned char *)esph - skb->data, 578 assoclen + ivlen + esp->clen + alen); 579 if (unlikely(err < 0)) 580 goto error_free; 581 582 if (!esp->inplace) { 583 int allocsize; 584 struct page_frag *pfrag = &x->xfrag; 585 586 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 587 588 spin_lock_bh(&x->lock); 589 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 590 spin_unlock_bh(&x->lock); 591 goto error_free; 592 } 593 594 skb_shinfo(skb)->nr_frags = 1; 595 596 page = pfrag->page; 597 get_page(page); 598 /* replace page frags in skb with new page */ 599 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 600 pfrag->offset = pfrag->offset + allocsize; 601 spin_unlock_bh(&x->lock); 602 603 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 604 err = skb_to_sgvec(skb, dsg, 605 (unsigned char *)esph - skb->data, 606 assoclen + ivlen + esp->clen + alen); 607 if (unlikely(err < 0)) 608 goto error_free; 609 } 610 611 if ((x->props.flags & XFRM_STATE_ESN)) 612 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 613 else 614 aead_request_set_callback(req, 0, esp_output_done, skb); 615 616 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 617 aead_request_set_ad(req, assoclen); 618 619 memset(iv, 0, ivlen); 620 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 621 min(ivlen, 8)); 622 623 ESP_SKB_CB(skb)->tmp = tmp; 624 err = crypto_aead_encrypt(req); 625 626 switch (err) { 627 case -EINPROGRESS: 628 goto error; 629 630 case -ENOSPC: 631 err = NET_XMIT_DROP; 632 break; 633 634 case 0: 635 if ((x->props.flags & XFRM_STATE_ESN)) 636 esp_output_restore_header(skb); 637 } 638 639 if (sg != dsg) 640 esp_ssg_unref(x, tmp, skb); 641 642 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 643 err = esp_output_tail_tcp(x, skb); 644 645 error_free: 646 kfree(tmp); 647 error: 648 return err; 649 } 650 EXPORT_SYMBOL_GPL(esp_output_tail); 651 652 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 653 { 654 int alen; 655 int blksize; 656 struct ip_esp_hdr *esph; 657 struct crypto_aead *aead; 658 struct esp_info esp; 659 660 esp.inplace = true; 661 662 esp.proto = *skb_mac_header(skb); 663 *skb_mac_header(skb) = IPPROTO_ESP; 664 665 /* skb is pure payload to encrypt */ 666 667 aead = x->data; 668 alen = crypto_aead_authsize(aead); 669 670 esp.tfclen = 0; 671 if (x->tfcpad) { 672 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 673 u32 padto; 674 675 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 676 if (skb->len < padto) 677 esp.tfclen = padto - skb->len; 678 } 679 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 680 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 681 esp.plen = esp.clen - skb->len - esp.tfclen; 682 esp.tailen = esp.tfclen + esp.plen + alen; 683 684 esp.esph = ip_esp_hdr(skb); 685 686 esp.nfrags = esp_output_head(x, skb, &esp); 687 if (esp.nfrags < 0) 688 return esp.nfrags; 689 690 esph = esp.esph; 691 esph->spi = x->id.spi; 692 693 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 694 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 695 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 696 697 skb_push(skb, -skb_network_offset(skb)); 698 699 return esp_output_tail(x, skb, &esp); 700 } 701 702 static inline int esp_remove_trailer(struct sk_buff *skb) 703 { 704 struct xfrm_state *x = xfrm_input_state(skb); 705 struct crypto_aead *aead = x->data; 706 int alen, hlen, elen; 707 int padlen, trimlen; 708 __wsum csumdiff; 709 u8 nexthdr[2]; 710 int ret; 711 712 alen = crypto_aead_authsize(aead); 713 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 714 elen = skb->len - hlen; 715 716 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 717 BUG(); 718 719 ret = -EINVAL; 720 padlen = nexthdr[0]; 721 if (padlen + 2 + alen >= elen) { 722 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 723 padlen + 2, elen - alen); 724 goto out; 725 } 726 727 trimlen = alen + padlen + 2; 728 if (skb->ip_summed == CHECKSUM_COMPLETE) { 729 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 730 skb->csum = csum_block_sub(skb->csum, csumdiff, 731 skb->len - trimlen); 732 } 733 ret = pskb_trim(skb, skb->len - trimlen); 734 if (unlikely(ret)) 735 return ret; 736 737 ret = nexthdr[1]; 738 739 out: 740 return ret; 741 } 742 743 int esp_input_done2(struct sk_buff *skb, int err) 744 { 745 const struct iphdr *iph; 746 struct xfrm_state *x = xfrm_input_state(skb); 747 struct xfrm_offload *xo = xfrm_offload(skb); 748 struct crypto_aead *aead = x->data; 749 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 750 int ihl; 751 752 if (!xo || !(xo->flags & CRYPTO_DONE)) 753 kfree(ESP_SKB_CB(skb)->tmp); 754 755 if (unlikely(err)) 756 goto out; 757 758 err = esp_remove_trailer(skb); 759 if (unlikely(err < 0)) 760 goto out; 761 762 iph = ip_hdr(skb); 763 ihl = iph->ihl * 4; 764 765 if (x->encap) { 766 struct xfrm_encap_tmpl *encap = x->encap; 767 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 768 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 769 __be16 source; 770 771 switch (x->encap->encap_type) { 772 case TCP_ENCAP_ESPINTCP: 773 source = th->source; 774 break; 775 case UDP_ENCAP_ESPINUDP: 776 source = uh->source; 777 break; 778 default: 779 WARN_ON_ONCE(1); 780 err = -EINVAL; 781 goto out; 782 } 783 784 /* 785 * 1) if the NAT-T peer's IP or port changed then 786 * advertise the change to the keying daemon. 787 * This is an inbound SA, so just compare 788 * SRC ports. 789 */ 790 if (iph->saddr != x->props.saddr.a4 || 791 source != encap->encap_sport) { 792 xfrm_address_t ipaddr; 793 794 ipaddr.a4 = iph->saddr; 795 km_new_mapping(x, &ipaddr, source); 796 797 /* XXX: perhaps add an extra 798 * policy check here, to see 799 * if we should allow or 800 * reject a packet from a 801 * different source 802 * address/port. 803 */ 804 } 805 806 /* 807 * 2) ignore UDP/TCP checksums in case 808 * of NAT-T in Transport Mode, or 809 * perform other post-processing fixes 810 * as per draft-ietf-ipsec-udp-encaps-06, 811 * section 3.1.2 812 */ 813 if (x->props.mode == XFRM_MODE_TRANSPORT) 814 skb->ip_summed = CHECKSUM_UNNECESSARY; 815 } 816 817 skb_pull_rcsum(skb, hlen); 818 if (x->props.mode == XFRM_MODE_TUNNEL) 819 skb_reset_transport_header(skb); 820 else 821 skb_set_transport_header(skb, -ihl); 822 823 /* RFC4303: Drop dummy packets without any error */ 824 if (err == IPPROTO_NONE) 825 err = -EINVAL; 826 827 out: 828 return err; 829 } 830 EXPORT_SYMBOL_GPL(esp_input_done2); 831 832 static void esp_input_done(void *data, int err) 833 { 834 struct sk_buff *skb = data; 835 836 xfrm_input_resume(skb, esp_input_done2(skb, err)); 837 } 838 839 static void esp_input_restore_header(struct sk_buff *skb) 840 { 841 esp_restore_header(skb, 0); 842 __skb_pull(skb, 4); 843 } 844 845 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 846 { 847 struct xfrm_state *x = xfrm_input_state(skb); 848 struct ip_esp_hdr *esph; 849 850 /* For ESN we move the header forward by 4 bytes to 851 * accommodate the high bits. We will move it back after 852 * decryption. 853 */ 854 if ((x->props.flags & XFRM_STATE_ESN)) { 855 esph = skb_push(skb, 4); 856 *seqhi = esph->spi; 857 esph->spi = esph->seq_no; 858 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 859 } 860 } 861 862 static void esp_input_done_esn(void *data, int err) 863 { 864 struct sk_buff *skb = data; 865 866 esp_input_restore_header(skb); 867 esp_input_done(data, err); 868 } 869 870 /* 871 * Note: detecting truncated vs. non-truncated authentication data is very 872 * expensive, so we only support truncated data, which is the recommended 873 * and common case. 874 */ 875 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 876 { 877 struct crypto_aead *aead = x->data; 878 struct aead_request *req; 879 struct sk_buff *trailer; 880 int ivlen = crypto_aead_ivsize(aead); 881 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 882 int nfrags; 883 int assoclen; 884 int seqhilen; 885 __be32 *seqhi; 886 void *tmp; 887 u8 *iv; 888 struct scatterlist *sg; 889 int err = -EINVAL; 890 891 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 892 goto out; 893 894 if (elen <= 0) 895 goto out; 896 897 assoclen = sizeof(struct ip_esp_hdr); 898 seqhilen = 0; 899 900 if (x->props.flags & XFRM_STATE_ESN) { 901 seqhilen += sizeof(__be32); 902 assoclen += seqhilen; 903 } 904 905 if (!skb_cloned(skb)) { 906 if (!skb_is_nonlinear(skb)) { 907 nfrags = 1; 908 909 goto skip_cow; 910 } else if (!skb_has_frag_list(skb)) { 911 nfrags = skb_shinfo(skb)->nr_frags; 912 nfrags++; 913 914 goto skip_cow; 915 } 916 } 917 918 err = skb_cow_data(skb, 0, &trailer); 919 if (err < 0) 920 goto out; 921 922 nfrags = err; 923 924 skip_cow: 925 err = -ENOMEM; 926 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 927 if (!tmp) 928 goto out; 929 930 ESP_SKB_CB(skb)->tmp = tmp; 931 seqhi = esp_tmp_extra(tmp); 932 iv = esp_tmp_iv(aead, tmp, seqhilen); 933 req = esp_tmp_req(aead, iv); 934 sg = esp_req_sg(aead, req); 935 936 esp_input_set_header(skb, seqhi); 937 938 sg_init_table(sg, nfrags); 939 err = skb_to_sgvec(skb, sg, 0, skb->len); 940 if (unlikely(err < 0)) { 941 kfree(tmp); 942 goto out; 943 } 944 945 skb->ip_summed = CHECKSUM_NONE; 946 947 if ((x->props.flags & XFRM_STATE_ESN)) 948 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 949 else 950 aead_request_set_callback(req, 0, esp_input_done, skb); 951 952 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 953 aead_request_set_ad(req, assoclen); 954 955 err = crypto_aead_decrypt(req); 956 if (err == -EINPROGRESS) 957 goto out; 958 959 if ((x->props.flags & XFRM_STATE_ESN)) 960 esp_input_restore_header(skb); 961 962 err = esp_input_done2(skb, err); 963 964 out: 965 return err; 966 } 967 968 static int esp4_err(struct sk_buff *skb, u32 info) 969 { 970 struct net *net = dev_net(skb->dev); 971 const struct iphdr *iph = (const struct iphdr *)skb->data; 972 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 973 struct xfrm_state *x; 974 975 switch (icmp_hdr(skb)->type) { 976 case ICMP_DEST_UNREACH: 977 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 978 return 0; 979 break; 980 case ICMP_REDIRECT: 981 break; 982 default: 983 return 0; 984 } 985 986 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 987 esph->spi, IPPROTO_ESP, AF_INET); 988 if (!x) 989 return 0; 990 991 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 992 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 993 else 994 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 995 xfrm_state_put(x); 996 997 return 0; 998 } 999 1000 static void esp_destroy(struct xfrm_state *x) 1001 { 1002 struct crypto_aead *aead = x->data; 1003 1004 if (!aead) 1005 return; 1006 1007 crypto_free_aead(aead); 1008 } 1009 1010 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1011 { 1012 char aead_name[CRYPTO_MAX_ALG_NAME]; 1013 struct crypto_aead *aead; 1014 int err; 1015 1016 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1017 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1018 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1019 return -ENAMETOOLONG; 1020 } 1021 1022 aead = crypto_alloc_aead(aead_name, 0, 0); 1023 err = PTR_ERR(aead); 1024 if (IS_ERR(aead)) 1025 goto error; 1026 1027 x->data = aead; 1028 1029 err = crypto_aead_setkey(aead, x->aead->alg_key, 1030 (x->aead->alg_key_len + 7) / 8); 1031 if (err) 1032 goto error; 1033 1034 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1035 if (err) 1036 goto error; 1037 1038 return 0; 1039 1040 error: 1041 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1042 return err; 1043 } 1044 1045 static int esp_init_authenc(struct xfrm_state *x, 1046 struct netlink_ext_ack *extack) 1047 { 1048 struct crypto_aead *aead; 1049 struct crypto_authenc_key_param *param; 1050 struct rtattr *rta; 1051 char *key; 1052 char *p; 1053 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1054 unsigned int keylen; 1055 int err; 1056 1057 err = -ENAMETOOLONG; 1058 1059 if ((x->props.flags & XFRM_STATE_ESN)) { 1060 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1061 "%s%sauthencesn(%s,%s)%s", 1062 x->geniv ?: "", x->geniv ? "(" : "", 1063 x->aalg ? x->aalg->alg_name : "digest_null", 1064 x->ealg->alg_name, 1065 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1066 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1067 goto error; 1068 } 1069 } else { 1070 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1071 "%s%sauthenc(%s,%s)%s", 1072 x->geniv ?: "", x->geniv ? "(" : "", 1073 x->aalg ? x->aalg->alg_name : "digest_null", 1074 x->ealg->alg_name, 1075 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1076 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1077 goto error; 1078 } 1079 } 1080 1081 aead = crypto_alloc_aead(authenc_name, 0, 0); 1082 err = PTR_ERR(aead); 1083 if (IS_ERR(aead)) { 1084 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1085 goto error; 1086 } 1087 1088 x->data = aead; 1089 1090 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1091 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1092 err = -ENOMEM; 1093 key = kmalloc(keylen, GFP_KERNEL); 1094 if (!key) 1095 goto error; 1096 1097 p = key; 1098 rta = (void *)p; 1099 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1100 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1101 param = RTA_DATA(rta); 1102 p += RTA_SPACE(sizeof(*param)); 1103 1104 if (x->aalg) { 1105 struct xfrm_algo_desc *aalg_desc; 1106 1107 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1108 p += (x->aalg->alg_key_len + 7) / 8; 1109 1110 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1111 BUG_ON(!aalg_desc); 1112 1113 err = -EINVAL; 1114 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1115 crypto_aead_authsize(aead)) { 1116 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1117 goto free_key; 1118 } 1119 1120 err = crypto_aead_setauthsize( 1121 aead, x->aalg->alg_trunc_len / 8); 1122 if (err) { 1123 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1124 goto free_key; 1125 } 1126 } 1127 1128 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1129 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1130 1131 err = crypto_aead_setkey(aead, key, keylen); 1132 1133 free_key: 1134 kfree_sensitive(key); 1135 1136 error: 1137 return err; 1138 } 1139 1140 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1141 { 1142 struct crypto_aead *aead; 1143 u32 align; 1144 int err; 1145 1146 x->data = NULL; 1147 1148 if (x->aead) { 1149 err = esp_init_aead(x, extack); 1150 } else if (x->ealg) { 1151 err = esp_init_authenc(x, extack); 1152 } else { 1153 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1154 err = -EINVAL; 1155 } 1156 1157 if (err) 1158 goto error; 1159 1160 aead = x->data; 1161 1162 x->props.header_len = sizeof(struct ip_esp_hdr) + 1163 crypto_aead_ivsize(aead); 1164 if (x->props.mode == XFRM_MODE_TUNNEL) 1165 x->props.header_len += sizeof(struct iphdr); 1166 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1167 x->props.header_len += IPV4_BEET_PHMAXLEN; 1168 if (x->encap) { 1169 struct xfrm_encap_tmpl *encap = x->encap; 1170 1171 switch (encap->encap_type) { 1172 default: 1173 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1174 err = -EINVAL; 1175 goto error; 1176 case UDP_ENCAP_ESPINUDP: 1177 x->props.header_len += sizeof(struct udphdr); 1178 break; 1179 #ifdef CONFIG_INET_ESPINTCP 1180 case TCP_ENCAP_ESPINTCP: 1181 /* only the length field, TCP encap is done by 1182 * the socket 1183 */ 1184 x->props.header_len += 2; 1185 break; 1186 #endif 1187 } 1188 } 1189 1190 align = ALIGN(crypto_aead_blocksize(aead), 4); 1191 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1192 1193 error: 1194 return err; 1195 } 1196 1197 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1198 { 1199 return 0; 1200 } 1201 1202 static const struct xfrm_type esp_type = 1203 { 1204 .owner = THIS_MODULE, 1205 .proto = IPPROTO_ESP, 1206 .flags = XFRM_TYPE_REPLAY_PROT, 1207 .init_state = esp_init_state, 1208 .destructor = esp_destroy, 1209 .input = esp_input, 1210 .output = esp_output, 1211 }; 1212 1213 static struct xfrm4_protocol esp4_protocol = { 1214 .handler = xfrm4_rcv, 1215 .input_handler = xfrm_input, 1216 .cb_handler = esp4_rcv_cb, 1217 .err_handler = esp4_err, 1218 .priority = 0, 1219 }; 1220 1221 static int __init esp4_init(void) 1222 { 1223 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1224 pr_info("%s: can't add xfrm type\n", __func__); 1225 return -EAGAIN; 1226 } 1227 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1228 pr_info("%s: can't add protocol\n", __func__); 1229 xfrm_unregister_type(&esp_type, AF_INET); 1230 return -EAGAIN; 1231 } 1232 return 0; 1233 } 1234 1235 static void __exit esp4_fini(void) 1236 { 1237 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1238 pr_info("%s: can't remove protocol\n", __func__); 1239 xfrm_unregister_type(&esp_type, AF_INET); 1240 } 1241 1242 module_init(esp4_init); 1243 module_exit(esp4_fini); 1244 MODULE_DESCRIPTION("IPv4 ESP transformation library"); 1245 MODULE_LICENSE("GPL"); 1246 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1247